Implantable medical devices (IMDs) include devices designed to be implanted into a patient. The devices can be used to treat patients using electrical or other therapy or to aid a physician or caregiver in patient diagnosis through internal monitoring of a patient's condition. Thrombosis is an obstruction of an artery or vein by a blood clot or thrombus. Thrombosis may result in ischemia. Thrombosis may occur in patients who develop atherosclerosis or have coronary artery disease (CAD), heart failure (HF), atrial fibrillation (AF), stroke, or other medical situations. Some clinical interventions, such as a stent procedure or treatment of anemia in HF patients, increase the risk of thrombosis. Vasoconstriction is an obstruction of an artery or vein due to a decrease in the diameter of blood vessels. Vasoconstriction may also result in ischemia. It is desirable to mitigate blood vessel obstructions or the risk of obstructions and to restore or promote adequate blood flow in blood vessels.